Tubular container



Aug. 8, 1944. M. D. DOUGLAS 5 2,355,584

TUBULAR CONTAINER Filed May 15, 1959' l VENTOR yoke/s .D. fiat/ 44s ATTO RN EYS Patented Aug. 8, 1944 TUBULAR CONTAINER Morris D. Douglas, Willoughby, Ohio, assignor to The Cleveland Container Company, Cleveland, Ohio, a corporation oi Ohio Application May 15, 1939, Serial No. 273,669

7 Claims.

This invention relates to improvements in electrical condensers and more particularly to improvements in the tubes or containers for electrical condensers.

Condensers of the type referred to are wellknown and are widely employed wherever capacitors having a fixed capacity are required. Such condensers are commonly comprised of wound lectrodes of metal foils spaced by paper or similar dielectric materials. It is also common practice to impregnate such wound condenser bodies with a borate paste or a similar filming electrolyte.

Heretofore, it has been the usual and accepted practice to seal such wound condenser bodies in a metal capsule or tube, usually of drawn aluminum or similar material. The function of the metal tube is to provide mechanical support for the condenser body and to protect the condenser body from water, oil, dirt, moisture vapor and similar elements which affect the characteristics of the condenser and cause breakdown. The metal tube or capsule is usually wrapped with a snugly fitting paper or cardboard tube. This tube serves to insulate the metal tube from contact with exposed leads and also serves as a label which carries the manufacturers name and a statement of the capacity and other characteristics of the condenser.

It is an object of this invention to provide an improved condenser tube which is light, rugged, inexpensive, and which will perform the functions of the metal capsule and the enveloping cardboard tube used heretofore. More specifically, it is an object of this invention to provide a condenser tube of spirally wound paper stock provided with a suitable lining so that the structure is water-proof, oil-proof, and, especially, moisture-vapor-proof.

It is another object of this invention to provide a condenser tube which will increase the overload rating of the condenser and prolong its life. More specifically, it is an object of this invention to provide a container for condensers or similar electrical elements which will absorb the heat generated during the use of the element and which will dissipate the absorbed heat to the ambient atmosphere. A further object of this invention is to provide a container which is inert to the compounds impregnated in the condensers. 1'

Other and further objects will become apparent from the following specifications, claims, and drawings, in which Fig. 1 is a longitudinal section of the improved condenser tube.

Fig. 2 is a fragmentary view of thelaminated liner used in the improved condenser tube.

Fig. 3 is a section taken along the line 3-3 of Fig. 2.

Fig. 4 is a detail of the lap scam in the inner liner.

Fig. 5 is a diagrammatic sectional view showing a completed condenser employing the improved tu-be.

As illustrated in the drawing, in which like reference characters refer to like parts, the condenser tube. 5 is comprised of an outer body portion In which is formed or strong paper stock, such as kraft' paper, cardboard, fiberboard, chipboard, or the like. As shown in Fig. l, the body 10 is preferably formed of a plurality oi. spirally wound plies II and -l2'laid with the seams out or register and laminated together. The outer surface of the body l0 consists of a ply of silvered paper l3 which has been glazedto render it more or less water resistant.

The primary purpose of the outer body III is to serve as a strong and rigid support for the inner liner 20, which gives the structure 5 its oil-proof, water-proof, moisture-vapor-proof and heat absorbing and radiating properties. As shown in Figs. 2 and 3. the liner 2l l is comprised of a thin paper backing strip 2|, to the face of which is laminated a strip of metal foil 22. A strip of film 23 is laminated to the face of the foil 22 by a suitable adhesive 24. The strip or water-proof film 23 is wider than the laminated strips of paper and foil, the marginal portion 25 being turned over and laminated to the back of the paper strip 2|.

The liner 20 is formed by winding the laminated strip of paper, foil, and film so that lower edge of one turn of the strip overlaps and engages the overturned marginal portion 25 of the preceding turn, thereby forming the lap seam illustrated in Figs. 1 and 4. This operation is usually performed on a mandrel, and as the liner 20 is formed, it is the preferred practice to wind the several layers of paper stock ll, l2, and on the liner 20. Thus, a long tube is formed in which the liner 20 and the outer body ID are united into an integral structure by the use of suitable adhesives. The long integral tube is then cut into proper lengths, thereby forming a plurality of tubes 5.

The completed condenser, illustrated diagrammatically in Fig. 5, is formed by inserting a wound condenser body 30 into the condenser tube 5.

' abl sealing or "potting? compound 22.

The strip of film 23 is preferably cellulose acetate sheeting, although other water-proof sheetings may be employed, especially if they possess the desirable characteristics of cellulose acetate. The function of the film 23 is to provide a tough, water-proof, and chemically inert lining face for the condenser tube. Cellulose acetate film performs these functions because it possesses the required strength, it is water-proof per se and does not depend upon a coating of wax or lacquer to render it water-proof, and it is chemicallyinert to the various electrolytes which may be impregnated in the condenser body. The inertness of the cellulose acetate film apparently is attributable to the fact that it is free from residues of strong caustics or similar regenerating agents which may be present in other films available commercially. Unless the film 23 is substantially inert, a harmful electrolysis may be set up between the film and the electrodes in the condenser body.

The primary function of the adhesive 24 is, of course, to adhere the film 22 to the foil 22. For example, a lacquer-base adhesive comprising a natural or synthetic resin and a plasticizer may be used. Such a lacquer-base adhesive may also include a cellulose derivative, such as cellulose acetate or the like. Or the adhesive may be simply a natural or synthetic plastic resin possessing a requisite degree of adhesiveness.

The suitable adhesives for laminating the film 23 to the foil 22 are normally transparent and since the film 22 is also normally transparent, the bright face of the foil 22 tends to reflect the heat generated by the condenser body 30 during normal loads and, especially, during overloads. Because the heat generated during an excessive overload may raise the temperature of the condenser body to nearly the charring point of the dielectric in the condenser body, the adhesive 24 is preferably pigmented to absorb the heat radiated by the condenser body and to prevent the bright face of the foil 22 from reflecting radiated heat back into the condenser body. A suitable black pigment, such as carbon black, bone black, or the like, is, therefore, thoroughly milled or mixed with the adhesive 24 to render it opaque. The proportion of the black pigment to the adhesive may vary from per cent to 50 per cent, depending upon the opacity of the pigment used and the thickness of the adhesive 24. Although a black carbonaceous pigment is preferred, any pigments which absorb and do not reflect radiations greater than .75 micron in wave length may be used.

Although the film 23 of cellulose acetate is impervious to water, and nearly all other liquids, it is not impervious to water-vapor. It is obviousjhat if the condenser tube 5 were permeable to water-vapor, the humidity of the ambient atmosphere would affect the characteristics of the condenser, since the presence of water-vapor in the condenser body would weaken the dielectric strength of the spacers between the electrodes. Furthermore, the electrolyte impregnated in the condenser is often more or less hygroscopic, and the swelling of the electrolyte due to the absorption of water-vapor could cause a mechanical as well as an electrical breakdown of the condenser.

The primary function of the metal foil 22, therefore, is to render the liner moisture-vapor Suitable leads 2| extend beyond the ends of the proof. Preferably, aluminum foil of a thickness of .00035 of an inch is employed, although any other metal foil, such as tin foil, lead foil, or the like, maybe used.

Because the thin paper backing strip 2| and the outer tube l0 are non-opaque to radiant heat, the metal foil 22 serves an important secondary function in dissipating the heat generated in the condenser body. If the adhesive 24 is pigmented according to the preferred form of this invention, the heat absorbed by the adhesive is transferred to the foil 22 by conduction and is then dissipated from the outer face of the foil. Even if the adhesive 24 is not pigmented, so that a certain amount of heat may be reflected back into the condenser body by the inner face of the foil, the outer face of the foil is an excellent heat- -dissipating surface. Thus, the temperature of the condenser body will not exceed the charring point of the dielectric except under extremely severe overloads.

Because the thin paper backing strip 2| is porous, it may be laminated to the outer face of the foil 22 by an ordinary gelatinous water-soluble adhesive. In the preferred construction the backing strip is twenty-pound white bond paper. The paper and foil are usually laminated by the manufacturer of the metal foil and the laminated material is available commercially in large sheets or webs. The paper backing strip serves the functions of protecting the foil 22, reinforcing the film and providing a porous outer surface for the liner 20 so that the liner may be strongly adhered to the outer body ID by the use of ordinary water-soluble adhesives.

The lap seam illustrated in Figs. 1 and 4 is substantially the same as that disclosed in the U. S. patent to Schmidt, No. 2,110,843. This lap seam is employed in the preferred form of this invention because it ail'ords a film-to-film contact between adjacent turns of the laminated lining strip so that the inner surface of the liner 20 presents a continuous film surface. Also, all portions of the film 23, and especially that portion of the film at the lap seam, are reinforced by the paper strip 2i so that rupture of the film due to shrinkage and embrittlement with age is prevented. A lacquer-base adhesive can be employed to adhere to overturned marginal portion 25 of the film 23 to the face of the adiacent turn of the laminated lining strip, although a suitable film solvent, such as Cellusolve may be employed to weld the overturned edge of one turn of the strip to the face of the adjacent turn. If a thermoplastic film is employed, a heat seal may be used to unite the successive turns of the liner. The thickness of the liner 20 and of the lap seam therein has been exaggerated in Figs. 1 and 4 to show the construction clearly. Actually, because of the thinness of the paper, foil and film employed, the seam is scarcely perceptible.

Because the outer face of the liner 20 and the helically wound strips of paper stock II and I2 and the covering paper l3 are all porous, an ordinary water-soluble adhesive can be used to bond the liner 20 and all the elements in the outer body In into a strong integral structure. The surface of the paper I: is preferably glazed to render it water-resistant. Powdered aluminum may be incorporated in the glaze to give the tube an attractive appearance and to assist in the dissipation of heat from the condenser.

A condenser tube made according to the present invention is lighter and less expensive than the metal tubes used heretofore while providing the same amount of mechanical support and protection. A condenser tube made according to this invention is superior to containers used heretofore in that it dissipates the heat generated during loads on the condenser rapidly and efficiently by radiation.

It is to be understood that this disclosure of the present invention is not limited to condensers alone, but that it may be used for electrical resistors, inductors, or any other elements which must be protected from the adverse effect of water, moisture vapor, and heat. It is also to be understood that the invention may be used for containers for substances which must be protected from the deleterious effects of water, oil, or moisture vapor or for substances containing liquid or volatile elements. This invention, therefore, is not restricted to the preferred embodiment disclosed, either in whole or in part, but it is restricted only by the following claims.

What is claimed is:

1. As an article of manufacture, a container comprising an outer supporting tube and an inner relatively impervious liner comprising an outer lamina of substantially vapor-proof foil and an inner lamina of substantially water-proof film adhered to and covering said foil, said outer supporting member being relatively rigid with respect to said liner.

2. As an article of manufacture, a container comprising a rigid outer supporting tube and a liner comprising a paper backing member, a vapor-proof metal foil laminated to said backing member, a substantially inert liquid-proof film, and an adhesive adhering said film to said foil.

3. As an article of manufacture, a container comprising a rigid outer body member of laminated paper stock and a spirally wound liner adhered to said body member, said liner comprising a paper backing strip, a strip of vapor-proof metal foil laminated to the face of said backing strip, a strip of liquid-proof film, an adhesive adhering said film to the face of said foil, and an overturned marginal portion of said film adhered to the back of said backing strip.

4. As an article of manufacture, a container comprising a rigid outer supporting tube and a liner comprising a paper backing member, a vapor-proof metal foil laminated to said backin member, a substantially inert liquid-proof film of cellulose acetate, and an adhesive adhering said film to said foil,

5. As an article of manufacture, a container comprising a rigid outer body member of 1aminated paper stock and a spirally wound liner adhered to said body member, said liner comprising a paper backing strip, a strip of vapor-proof metal foil laminated to the face of said backing strip, a strip of liquid-proof film of cellulose acetate, an adhesive adhering said film to the face of said foil, and an overturned marginal portion of said film adhered to the back of said backing strip.

6. As an article of manufacture, a container comprising a rigid outer supporting tube and a liner comprised of a strip of substantially vaporproof metal film, a strip of substantially inert water-proof film, and a colored adhesive adhering said film to said foil.

1. As an article of manufacture, a container comprising a rigid outer body and a helically wound liner adhered to said outer body member comprising a strip of substantially liquid-proof film having an overturned marginal portion, a narrower strip of vapor-proof metal foil included between said strip of film and said overturned marginal portion, and a pigmented heat absorbing adhesive adhering said foil to said film.

MORRIS D. DOUGLAS. 

